Proximity-based applications and services represent a fast growing social and technological trend that may have a major impact on the evolution of cellular wireless/mobile broadband technologies. These services are based on the awareness that two devices or two users are close to each other and, thus, may be able to directly communicate with each other. Proximity-based applications include social networking, mobile commerce, advertisement, gaming, etc. It is desirable to have a method of discovering when other devices capable of Device-to-Device (D2D) communication are in the proximity of a D2D capable device.